Titanium is used in many applications requiring high strength but relatively low weight parts and components. Titanium is highly reactive (i.e., prone to oxidize) when formed under heat and/or welded at temperatures of over 500° F., and particularly over temperatures of 900° F. However, these high temperatures are sometimes required for weld repair processes and heat treatments, which may be necessary to fix mis-drilled holes, oversize holes, dents in the surface of a honeycomb panel, etc. At these high temperatures, the titanium may react with oxygen in the air and other contaminants present, becoming brittle and prone to cracking unless properly shielded from atmospheric gasses.
Conventional heat treating for stress relief of net or near net shape titanium parts are performed inside a vacuum furnace or alternatively in an argon chamber to prevent surface reaction/contamination when titanium is at heat treatment temperature. For example, the titanium requiring heating may be prevented from reacting with components of air, water, oxygen, and carbon dioxide by insertion into an enclosed chamber or vacuum furnace evacuated of air and other contaminants. A high vacuum removes air from within the chamber, and an inert gas, such as argon, may be introduced in its place. However, the equipment for this technique can be expensive and involves placing the entire part into the chamber for heating. The entire titanium part is therefore heated, even though only a portion of the part may actually require heat treating. In the case of repair, the titanium part may need to be removed entirely from an aircraft to be placed into the chamber.
Thus, prior art methods of heat-treating titanium tend to be inefficient, expensive, and time-consuming.